Method and apparatus for electrical regulation



June 30, 1925. I 1,543,863

F. w. MERRILL METHOD AND APPARATUS FOR ELECTRICAL REGULATION Filed Aug. 24, 1921 /7 a 426 a /6 a a 304g 26 i gzfl vnriablcvolfaqe I Suppl Line Dnfnbufwn Line Awe/War: Fran/r W Mew/7W Patented June 30, 1925.

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MK W. MERRILL, OF EAST ORANGE, NEW JERSEY, ASSIGNOR '10 WESTERN ELEC- rmo conmmr, mcoaromrn'n'or new YORK.

To all whom it concern.

Be it known that I, FRANK W. Manama, a citizen of the United States of America residing at East Oran e, in the county of Essex and State of ew Jersey, have invented certain new and useful Improvements apparatus for electrical regulation and has articular reference to a reci rocating ooster system which automatica ly main-' tains the voltage of a distribution circuit at a desired value.

The primary object of the invention is to rovide a smoothly operating system which 18 sufliciently flexible to respond instantaneously to every degree of variation in thevoltage of a su ply circuit so as to maintain the voltage 0 a distribution circuit substantially constant. a

A further object of the invention is to rovide the above regulating system with a oad compensating device which upon increase of the load in the distribution circuit will operate to increase the voltage of said circuit a predetermined amount above the light load regulating point. Means are provi ed for ad uSting t is load compensating device.

Another objectvof the invention is to provide an apparatus which operates continuously but which functions in its regulative ca acity only when an adjustment in the v0 tuge of the distribution circuit is reuired. The advanta e of this feature is t iat both the time an energy which would otherwise be necessary for rapidly startin and stopping the apparatus are economize A still further object of the invention is to provide a dynamo electric machine the strength and polarity of whose field may be determined and controlled by varyin the strength of one of two differential win ings which comprise the field.

More specifically the invention relates to a balancing or reciprocating booster system comprising a pair of shunt wound dynamo electric machines which are mounted upon a common shaft, and which function together as a. motor generator unit. Either machine may operate as a motor to drive the other as a generator without change in shunt field windin two differentiall YORK, 11. Y., A oonromrron or new mnon Ann armrest ron. msc'rmcu. uncommon. Ya uuma 1101! As an as, am. semi no. can.

the direction of rotation of the two machines. One of the machines and is connected across the two main lea s of the supply circuit,

has a single,

whereas the other machine is in series in l the branch ordistribution circuit and has wound shunt field coils. One of these fie d coils has in its circuit a voltageregulator which is resgonsive to the voltage'and the current of sai distribution circuit. The voltage regulator is connected so as to varythe amount of resistance in series with this field coil and to thus control its ma netomotivehforce; The range of this contro is suchthat the ampere turns of the regulated coil may be made less than, equal to, or greater than those of the other of said differential coils according as the voltage of the supply circuit is greater than, equal to, or lessthanthe regulated voltage of the distribution circuit.

The accom anying drawing illustrates" a,

electrical supply circuit havin leads 10,11,

upon which a varying potentia is impressed, furnishes energy through the im roved regu-- lating system to a distribution circuit whose leads are shown at 12 and 13. This circuit serves to energize a series of motors or equivalent translating devices (not shown? the combined power demands of whic create a variable demand for power in the circuit. The im roved regulating s stem com rises the fol owing: a dynamo e ectric mac line having its armature or rotor 14 bridged across the leads of the supply circuit and provided with a shunt windin 15 which enables it to rotate in the same direction while functioning either as a motor or a generator. Mechanically connected to the rotor 14 by means of shaft 16, or other suitable means, is a second rotor 17 which is energized in series with the distribution circuit. Two differentially wound shunt fields Y 18 and 19 cooperat'rn with the armature 17 are energized from t e supply and distribu- 20 and 21. The winding 20 is energized from a shunt in the distribution circuit, having one lead 23 attached to a fixed contact 25 and the other lead 24 adj ustably connectcd to a metal bar 22. The second winding 21 has one of its leads 26 permanently attached to lead 12 of the distribution circuit at a point 27 and its other lead 28 attached to lead 13 of the distribution circuit through an adjustable resistance 29. Armature 31 of the voltage regulator vibrates rapidly across a resistance 30 in series with coil 19 in a well-known manner, varying the current in coil 19 so as to maintain the resultant flux of coils 20 and 21 of the voltage re ulator substantially constant.

lhe operation or" the system is as follows: The rotors 1 1 and 1? operate continuously in one direction. ri lion the voltages of the supply and distribution ends of the circuits are equal, armature 17 will be generating just enough voltage to overcome the drop through its winding and brush contacts, while armature 1 1 will draw only sufiicient power from the supply service to overcome the losses of the set and to supply the small amount of energy needed for the generator action of armature 17. If the voltage of the supply service now decreases below the regulating point for which the voltage regulator is set, the distribution circuit voltage will decrease very slightly allowing armature 31to remain in contact with point 32 for a longer eriod of time in its vibrations, thus stren honing field 19 and causing armature 1 to generate sufficient voltage to make up for the decrease of the volta e in the supply service. Armature 14 will draw sufiicient additional energy from the supply line to enable it to drive armature 17 with its increased load. The speed of the set will decrease slightly. On the-other hand, if the voltage of the supply service increases above the re lated point, the voltage of the distribution circuit will increase very slightly causing armature 31 to remain out of contact with point 32 for a longer time in its vibrations, weakening field 19 until its magneto motive force is less than that of coil 18. The resulting flux of the series unit of the regulating set will then reverse, causing armature 17 to generate a voltage counter to that of the sup ly service. The series unit of the set" thus ecomes a motor and the speed of the set rises, causing armature 14 to general a voltage higher than that of the supply service and to pump current back into the supply line until torque equilibrium between armatures 14 and 17 is restored.

Changes in motor load on the distribution network may occur at any time irrespective of changes in the voltage of the su ply circuit, and at such time it is desirab e to increase the network voltage so as to partly offset the i. r. drop in the armature winding of the motors caused by the increased load, thus maintaining the speed of the motors substantially constant. This is accomplished by differentially connectin the coil 20 of the voltage regulator whic opposes the ampere turns of the coil 21 more strongly with increased load, necessitating an increase in the ampere turns of the coil 21 to maintain the resultin magneto motive force of the voltage regu ating coils constant. It is thus apparent that the effect of increased current drawn by the distribution circuit is to set the regulating point of coil 21 for a higher voltage. The amount of the increase 0 voltage obtainable in this way may be varied by adjusting the point of connection of coil 20 to shunt 22.

Since coil 19 has a greater number of ampere turns than coil 18, it can therefore be regulated so as to have a greater, equal or less magneto motive force than coil 18 which is subject only to the slight variations in potential across the main supply leads. In actual operation, armature 31 is in constant vibration, as already noted, regulating the strength of coil 19 for the slig test change in the voltage or load of the distribution circuit, varying the voltage of armature 17 both in amount and polarity with reat flexibility and responding to every minute degree of variation in the circuit within the limits of accuracy of the voltage regulator.

It should be understood that this invention is not limited to the use of the vibrat ing type of voltage regulator shown in the drawing. Any type of regulator which will automatically vary the ampere turns of field 19, may be used, or in the event of the failure of the regulator, resistance 30 may be operated by hand.

What is claimed is:

1. In combination with a system of electrical distribution, a shunt wound motor generator across the supply end of said system, a second motor generator mechanically connected to the first and connected to the load end of said system, said second machine having two differentially wonnd shunt fields, and means for controlling the current through one of said fields whereby said field may be stronger, equal to or weaker than the other.

2. In combination with a system ofelectrical distribution, a regulating system comprising a shunt wound motor generator across the supply end of said system, a second motor generator coupled with the first and connected in series with the load end of said s stem, two differentially wound shunt fields or said second motor generator, a voltage regulator in said load circuit serving to control the amount of current passing through one of said differential fields.

3. In a system of electrical distribution a main circuit and a branch circuit, a dynamo electric machine in shunt in the main circuit, a second dynamo electric machine in series in said branch circuit, a air of differential shunt field windings fiir said last named machine, and means by which the strength and polarity of said machine may be controlled.

4. In a system of electrical distribution, a shunt wound dynamo electric machine a second dynamo electric machine having differential y wound shunt field coils, means for controlling the voltage andv polarity of said second dynamo electric machine comprising an electromagnetic switch device responsive to the voltage and load of the circuit in which said second dynamo electric machine is connected for controlling the current in one of said difierential'field coils.

5. In a system of electrical distribution, a

main circuit and a branch circuit, means for regulating the voltage'of the branch circuit comprising a shunt wound dynamo electric mac ine energized by the main circuit, a

' second dynamo electric machine ener ized in series with said branch circuit, two unt fields for said second dynamo electric machine, and means in circuit with one of-said shunt fields for automatically regulating the voltage in said field in accordance with the load and voltage in said branch circuit.

6. In an electrical system, a source of current and two main leads therefor, a dynamo" supply circuit and a distribution circuit, a

electric machine in circuit across said leads, a branch circuit and two leadstherefor, a second dynamo electric machine in series with one of said leads, said second machine having ermanentmechanical connection with sai first machine, a pair of fields for said second dynamo electric machine,-means in the circuit of'one of said fields responsive to the volta and load in said circuit for controlling e energization of said field.

7. In a voltage regulating system, a supply circuit, a booster device comprising a pair of dynamo electric machines mechani cally connected to each other, one of said machines being connected across said supply circuit, a shunt field windin for said machine, a distribution circuit, 0 second machine being connected in series in the districircuit comprisin bution,circuit, andhavin a pair of difiershunt fields, said device being responsive to the load and voltage of the distribution circuit.

8. In a voltage regulating system, a supply circuit, a dynamo electric machine connected across said supply circuit, a distribution circuit, a second dynamo electric machine coupled to the first and connected in series in said distribution circuit, a pair of differential shunt field windings for said second machine, an electromechanical device in circuit with one of said windings, whereby the current in said winding is controlled by means res onsive to the load and voltage of said distri ution circuit.

9. In a direct current electrical distributing system, a main circuit, a feeder circuit, an electrical balancing system for said feeder a shunt wound dynamo electric machine aving its field energized by said main circuit, a second dynamo electric machine mechanicall connected to the first, a pair of difierentia shunt field windings for said second machine, one of said windings being energized from the main circuit, the second of said windings ener ized from said feeder circuit and electromec anical means responsive to the voltage and load of the feeder circuit for determining the energization of the second difierential field.

10. In an electrical distributing s stem, a

reciprocating booster system in said distributin circuit comprising a dynamo electric mac ine energized by said suplply circuit, a second dynamo electric mac ine-mechanically connected thereto and energized in series with said distribution circuit, a pair of differential shunt field coils for said second machine, means for cutting resistance into and out of the circuit of one of said coils according as the voltage of said main circuit is above or below t at of the dis-- tribution circuit.

In witness whereof I hereunto subscribe my name this 22nd day of August A. D., 1921.

FRANK W. MERRILL. 

